1. Field of the Invention
The present invention relates to a configuration definition setup method for a disk array apparatus for setting configuration definition information used by the firmware of a disk array apparatus on which a number of disk devices for storing data are installed, and to a disk array apparatus, and more particularly to a configuration definition setup method for a disk array apparatus for making the storage size of the configuration definition information variable according to a different scale of a model, and to a disk array apparatus.
2. Description of the Related Art
Recently as various data are computerized and handled on computers, a data storage apparatus (external storage apparatus) which can efficiently store large volumes of data with high reliability, independently from a host computer which executes data processing, is increasingly more important.
For this data storage apparatus, a disk array apparatus comprising a great number of disk devices (e.g. magnetic disks and optical disks) and a disk controller for controlling these disk devices is used. This disk array apparatus can receive disk access requests simultaneously from a plurality of host computers and control a great number of disks.
User demands for such disk array apparatus vary, so models in a plurality of scales must be provided according to the purpose of a user. In other words, the number of disk devices to be installed changes depending on the purpose of a user. As a result various models are demanded, for example, from a large scale disk array apparatus which can control a disk device group comprised of several thousand or more disk devices with several hundred terabytes or more of storage capacity by itself, to a small scale disk array device which has several tens of disk devices.
A change of the configuration of the disk array apparatus means that it is necessary to set the configuration information for controlling the disk devices according to the scale. In other words, in the case of a disk array apparatus, the configuration information is the configuration definition in the firmware of the controller, and is internal information unique to the disk array apparatus. Examples are the information and status of each disk device being installed, the set up contents of LUN (Logical Unit Number) and a RAID group, the hardware status of the controller and the type of the installed adapter.
The minimum required memory size of the configuration information differs depending on the model. Conventionally in a computer system, the configuration information is automatically created according to the configuration of the connected devices, and is stored in memory (e.g. Japanese Patent Application Laid-Open No. H9-54744).
In a disk array apparatus, on the other hand, the configuration information itself is diverse depending on the model. For example, since the number of installed disks is several tens to several thousands, in the case of each model of product for the low end/mid-range where the number of installed disks is little, so configuration information creation firmware is created for each model because of the relationship with the memory to be installed. In the case of each model of product for high end where the number of installed disks is large, a memory for the configuration definition for the maximum number of disk devices that can be installed is secured, although firmware is the same for all the models.
With the conventional method for creating firmware for each model, the development cost increases and the evaluation-manpower thereof also increases, which may cause delays in providing new disk array apparatus to market.
With the conventional method for creating a configuration definition using common firmware, on the other hand, the memory capacity for the maximum configuration must be secured. This is because the required memory capacity is in proportion to the number of installed disk devices and to the number of LUNs (Logical Unit Number), so the required cache size of the memory changes depending on the model. Therefore the memory size to be installed in the disk array apparatus must be decided depending on the cache size and the memory size to be used for the configuration definition. This operation is extremely troublesome when the number of different models increases, so it is effective to fix the memory size to be used for the configuration definition to the size required for the maximum configuration.
However if the number of installed disk devices is different, the memory size to be used for the configuration definition also changes, so in the case of the conventional method of securing the memory size for the maximum configuration, unnecessary memory is installed. And installing unnecessary memory increases the price of the product, which runs counter to recent demands for a low price apparatus. In particular, for a model where an enormous number of disk devices are installed is demanded, with this method of securing the memory size for the maximum configuration for a great number of models in which the range of the number of installed disk devices is wide, the price of unnecessary memory becomes high with respect to the apparatus price which can no longer be ignored.